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By L. F. Willmott

The Bureau of Nines at Morgantown, W. Va., has been investigating, on a pilot plant scale, various methods of gasifying bituminous coal with oxygen and superheated steam to produce synthesis gas, as part of the broader program of finding new uses for coal. Differences in the pressure gasification methods used have depended on differences in the manner in which the pulverized coal is fed to the gasifier. One of the methods of feeding the coal that was investigated was the continuous, integrated coal-water slurry system. Goal and water were first mixed to produce a slurry; then the slurry was pumped through a heated coil. to evaporate the water fraction; the resulting steam was superheated, and some of it was separated so as to adjust the ratio of the residual steam to the coal fraction and make the resulting mixture suitable for partial combustion with oxygen in a pressure gasifier. Both before and during this reported3 developmental work it was necessary to make an extensive literature search into the technology of aqueous slurries in order to establish design criteria for the pilot plant and to correlate results of various phases of the work with that of other investigators, The pilot work coincided with the commercial development of a long-distance pipe- line for the transportation of coal as a coal-water slurry, and this fact tended to broaden the scope of the pilot plant work and the extent of the literature search. This bibliography is the compilation of the material that was collected.

Jan 1, 1963

By Sanjay Kumar Singh

The mechanics of load transfer in bord-and-pillar mining is not well understood despite the evolution of the art of pillar extraction over the last 20 years via trial and error (empirical) or Rock Mass Rating (RMR), simple monitoring and pillar extraction experiences at neighboring mines. Variations in geologic conditions and pillar extraction methods, along with a lack of comprehensive instrumentation programs for monitoring ground behavior during pillar recovery, are among the factors that make it difficult to predict how strata will respond to pillar extraction. Efficient and safe use of roof supports depends on the interaction between the designed support and coal strata. Of particular interest in this study is the mechanics of strata deformation as influenced by geologic conditions, pillar extraction methods and optimum support with load-bearing capabilities in strata control during mass exploitation of underground coal deposits required detailed investigation,?. To provide a better understanding of the mechanics of strata deformation, as researchers, we have collected data and reviewed measurements of convergence and stress in one mine of South Eastern Coalfields Limited (S.E.C.L.), i. e., in North Chirimiri Pondary Hills (NCPH) and have completed numerical modeling with FLAC software for (Fast Lagrangian Analysis of Continua modeling, Itasca India Consulting Pvt. Ltd.) for two typical pillar extraction plans. Stress distribution in the mine roof above pairs of roof supports was calculated to demonstrate how Resin roof bolt support installed support contributed to roof block movement control. It was shown that overall stress and roof-floor convergence patterns were most influenced by the stiffness of coal measure rocks and by pillar extraction sequences and layouts. Also, resin roof bolts and other support systems play a critical role in controlling stability of both the immediate roof and the main roof for a distance of up to 18 meters (i.e., working coal seam height X three times) above the seam. Installed supports provide unique strata control advantages over other types of secondary support by significantly reducing the time between mining and installation of the secondary support. Although resin roof bolts are similar to posts in stiffness and capacity, they are more effective than posts under static loads because they can yield and still maintain loads at nearpeak capacity(Singh, et al., 2006), whereas posts fail and lose their ability to limit mine roof deformation.

Jan 1, 2012

By Isadora Almeida Rosa

Aços baixo-carbono com microestruturas ferrítico-bainíticos, bifásico, ou multifásicos têm características apreciáveis para a indústria automobilística, pois, combinam resistência, ductilidade e conformabilidade, permitindo produzir chapas mais finas resultando na redução do peso. Com o intuito de avaliar as características mecânicas e microestruturais obtidas através da variação da temperatura de bobinamento, desenvolveu-se um estudo a partir de um aço baixo carbono com microadição de molibdênio e nióbio, onde se verificou a possibilidade de produzir um aço dual phase na forma de chapas laminadas a quente, em escala industrial. Pode-se verificar que para menores temperaturas de bobinamento, obteve-se melhor desempenho quanto ao aumento da resistência mecânica e garantia de uma alta ductilidade vinculados a um refino expressivo no tamanho de grão da matriz ferrítica em conjunto com uma segunda fase com evidência de ilhas de martensita.

Aug 16, 2017

By John R. McWilliams

This report is one of a series published by the Bureau of Mines describing methods and practices at various mines throughout the United States. A previous program, conducted from 1928 to 1939, was well received by the mining industry and technical institutions and provided much source material for engineering textbooks and technical handbooks. The stringent wartime demands on the mining industry, the rapidly changing postwar economic situation, and greatly accelerated technologic growth have combined to render many of the previous data obsolete. The objective of the present program is to assemble reliable technical information on mining methods and practices throughout the country and present it for the use of the mining industry, technical schools, textbook authors, and other interested persons. This report deals with the design and development of the Berkeley open- pit mine at Butte, Mont., owned and operated by The Anaconda Company. The Berkeley pit is but one facet of a well-organized and integrated copper-mining operation involving the entire Butte district. Vein-type mining, important for 75 years, is still in progress at depths from 600 feet to nearly 1 mile; on intermediate levels, low-grade ore left untouched by earlier vein-type mines is being extracted by block caving entire ore zones,3/ and secondarily enriched but lower grade near-surface portions of the same ore zones are being mined by open-pit operations (fig. 1). The Berkeley pit itself is named for the Berkeley mine, one of the old mines that extracted copper ore from high-grade veins in the area that now will be mined by open-pit methods.

Jan 1, 1959

By J. K. Richmond

This is a progress report summarizing more than 5 years of a long-range Bureau of Mines research program. The purpose of this program has been to investigate the fire and explosion properties of Green River oil shale in the Bureau's Experimental Mine, in laboratories, and in the field. The lean limits of explosibility of oil shale dust, by small-and large-scale tests, are reported as a function of grade, ignition source, and particle size. A limited number of laboratory tests on the autoignition of oil shale dust layers and the spontaneous combustion tendencies of oil shale are described. Moderate-scale rubble fire tests were conducted to determine flame spread rates as a function of ventilation flow. With the aid of a system to continuously monitor methane emissions in a deep oil shale mine, the characteristics of the methane flow are reported as a function of ventilation and blasting procedures, and are compared with gas yields from core samples. Tentative predictions as to the emission of the methane to be expected in deep oil shale mines, far from the outcrop, are offered. Brief reference is made to a parallel investigation into the fire and explosion hazards of oil shale mining and processing by a Bureau contractor; detailed results of the latter investigation are to be found in the contractor's reports.

Jan 1, 1982

By Harold Price

ONE year ago, that is in January, 1923, there had not been constructed a single oil-storage tank of 55,000-bbl. or more capacity with a completely electric welded roof and bottom. Today, there are at least fifty 80,000-bbl. storage tanks completed, or nearing completion, on which both the roofs and the bottoms are electric welded. It is the purpose of this paper to describe, in a general way, the construction of these FIG. 1.-ELECTRIC-WELDED SEAMS AND RIVETS OF BOTTOM IN 55,000-BBL. TANK AT EL DORADO, KANS., SHOWING ALSO PATCH PLATE WELDED TO BOTTOM. welded roofs and bottoms, and to give their advantages over riveted construction. All of the following data and conclusions were obtained from observations made during the welding of tanks by the Welding Engineering Co. at Texas City, Tex., and Tonkawa and Burbank, Okla. As far as can be determined, the first electric welding on large tankage was completed in May, 1922. At that time the Empire Companies of Bartlesville, Okla., discovered a badly leaking bottom in a 55,000-bbl. tank at El Dorado, Kans. They had considered concreting this bottom, but because of the much smaller cost, decided to try electric welding; so a- contract was given the Welding Engineering Co. of Bartlesville, Okla. In this instance, no new sheets were added, the bottom being repaired by electric welding of all seams and rivets, Fig. 1. In some places where the original rivets were missing, the holes were filled by welding; patch plates were also added at certain badly worn spots. This tank has since been in service over a year and half, but no other

Jan 6, 1924

By Edward L. McHugh, Louis J. Denes, Jami M. Girard

A prototype portable hyperspectral imager that operates in the visible and near-infrared ranges of the electromagnetic spectrum was field tested at an open-pit mine. The tests were sponsored by the Spokane Research Laboratory, National Institute for Occupational Safety and Health, as part of an investigation of remote sensing technologies for use in detecting and monitoring conditions in surface mines that could lead to catastrophic slope failure. The spectro-polarimetric imager, built at the Carnegie Mellon Research Institute, employs an acousto-optical tunable filter (AOTF) to control wavelength, a phase retarder to measure polarization signatures, and a digital camera and computer to capture data. The spectral range of the instrument is 450 to 1000 nm at 10-nm intervals. High-resolution hyperspectral images of highwalls, outcrops, hand samples, and drill core were collected in the field. Spectra from the images closely matched those of specific minerals present and were used to classify the images. The field tests were designed to examine the feasibility of using spectral imaging to assist in compiling objective geologic maps of mine highwalls and other hazardous slopes. Results illustrate the capability of the method to discriminate materials within the image, validating the concept of simplified spectral imaging. A contributing factor in many slope failures is the presence and distribution of mechanically incompetent, clay-rich altered rock in slope faces. Spectral features of clays and other minerals are more distinctive in the short-wave and mid-infrared part of the spectrum; the capabilities of the instrument need to be extended into this range to apply the AOTF-based technology to common geologic materials. A field-portable hyperspectral imager could find broad application in remotely identifying diverse materials from solids and coatings to gases.

By Charles E. Whieldon

Data on the oilfields in Mahoning, Columbiana, Carroll, Jefferson, and Harrison Counties, Ohio, were collected from scattered sources and compiled to make the information readily available to operators who may be interested in conducting secondary-recovery operations in the area. General geology, oil production, oil-productive acreage, core data, reservoir calculations by townships, and miscellaneous data and reference material are presented.

Jan 1, 1965

This chapter summarizes data on crude nonfuel mineral production for the United States, its island possessions, and the Commonwealth of Puerto Rico. Also included are tables that show the principal nonfuel mineral commodities exported from and imported into the United States and that compare world and U.S. mineral production. The detailed data from which these tables were derived are contained in the individual commodity chapters of Volume I and in the State chapters of Volume II of this edition of the Minerals Yearbook. Although crude mineral production may be measured at any of several stages of extraction and processing, the stage of measurement used in this chapter is what is normally termed "mine output." It usually refers to minerals or ores in the form in which they are first extracted from the ground, but customarily includes the output from auxiliary processing at or near the mines.

Jan 1, 1988

Research into the mechanisation of ore winning from the very narrow reefs characteristic of South African gold mines has been conducted from as early as 1964 through the Chamber of Mines Research Organisation (COMRO) but with limited success. However, the Council for Scientific and Industrial Research (CSIR) has recently re-evaluated the potential for the mechanisation for the narrow tabular gold mines. It has been determined that there are approximately 22 000 tonnes of gold left in-situ in channel widths of less than 500 mm in thickness. The extraction of ore from such reefs requires a complete paradigm shift in that the current mining cycle (drilling, blasting, cleaning and supporting) is not feasible since such a stoping width would not allow the workers entry into the stope. Consequently, a non-entry form of mining is required. With this target in mind CSIR has invested in a project called the Nederburg Miner which seeks to identify new technologies for drilling, rock breaking, cleaning, and materials handling, the application of which will enable non-entry mining of very narrow ore bodies. The intention is to develop a fully automated system that will not require human involvement at the stope face. The outcomes of research into this proposed system will not only extend the life of South African gold mines but will also enhance South Africa's reputation for excellence in mining research. This paper presents the new technologies under consideration and potential methods for their application into an integrated non-entry mining system.

Jan 1, 2008

By J. Olsson

Introduction Stainless steel has by tradition been a common construction material for hydrometallurgy processes and the most common grades can be found amongst the ASTM 300-series, i.e. austenitic grades of type 304L, 316L and 317L. However, there are a number of new grades available today, which imply more cost effective solutions for those designing plants where good resistance to acids, containing the desired metal ions, often contaminated with chlorides and other halides, is the key issue. There are austenitic-ferritic or duplex grades having the same or even better corrosion resistance than the austenitic grades and approximately twice the strength, which enables design in thinner gauges, which in turn implies less weight and less cost. They have also excellent engineering properties, enabling fabrication of process equipment, machinery and different types of tanks. On top of that, they contain less nickel and molybdenum than their austenitic counterparts, which implies not only lower cost for alloying elements, but also a more stable price when considering the price fluctuations for these alloying elements during the last years. This paper describes briefly the family of duplex stainless steel and it presents a number of relevant corrosion tests where duplex grades have been compared with austenitic grades. The results have in several cases been verified by in-plant exposures in zinc and copper production plants. It also describes applications and experience of duplex grades within a variety of hydrometallurgy plants. Installations of highly alloyed austenitic grades will be described as well. The corrosion tests and service experience reported cover hydrometallurgical processes based on sulphuric acid.

Jan 1, 2007

By D D. Deacon

A brief description is given of the requirements which No. 4 Shaft has been designed to meet and of the methods by which two-stage winding of rock has been accommodated in a single shaft sunk to a depth of 7,421 ft. This is followed by a consideration of the factors which led to the decision to sink the shaft as rapidly as possible. Introduction T HE No. 4 Shaft of Hartebeest-fontein Gold Mining Company, Ltd., has been sited to serve the deep southern area of the mine, some 1,500 claims in extent, between the elevations of 6,250 and 7,300 ft. below surface. From this area, some two-thirds of the mine production will ultimately be obtained. Above the 6,-250-ft. elevation, an existing shaft hoisting system, situated adjacent to the reduction plant, is of adequate capacity to cater for all ore hoisted to surface for milling. No. 4 Shaft will therefore be required to provide downcast ventilation of 1,000,000 c.f.m., together with surface hoisting facilities for men, material and development rock and underground hoisting

Jan 1, 1965

By M P. Simpson, J L. Mauk

The Golden Cross, low-sulfidation, epithermal deposit shows a number of features that are directly or indirectly related to boiling hydrothermal fluids. Occurrences of lattice calcite and their quartz pseudomorph equivalents in veins, and occurrences of adularia in veins and in the surrounding altered rocks in the vicinity of ore, are both direct evidence of deposition in the presence of boiling hydrothermal fluids. Loss of carbon dioxide causes calcite deposition (platy variety) near the level of first boiling, while adularia deposits due to the attendant pH increase along the cooling flow path. Indirect evidence of boiling include crustiform-colloform quartz banding, late massive calcite veins, clay-carbonate alteration in the shallow and peripheral parts of the ore zone, and the restricted vertical interval of precious metal mineralisation. The colloform quartz banding strongly resembles the banding in amorphous silica deposits found in geothermal surface pipes. This implies that fluids ascending the Empire Vein structure were saturated in amorphous silica. If so, then they must have undergone phase separation, which initiated at considerable depth (e.g. =1000 m) and very hot temperatures (e.g. =300¦C). On the basis of stable isotope data, late massive calcite veins appear to have deposited from CO2-rich steam-heated waters. Calcite deposited along heating paths as these waters descended into the upflow zone during late stage collapse of the hydrothermal plume. In active systems, such steam heated waters form by deep boiling. The high CO2 contents of these waters promote hydrolytic alteration and the formation of clay-carbonate alteration. Reaction path modelling using CHILLER and a deep, Broadlands-Ohaaki water as an analogue, shows that minerals deposit along boiling flow paths over discrete spatial intervals. Calcite and adularia deposit near the site of first boiling, followed by gold and then by amorphous silica. For deep boiling starting at 300¦C, these minerals deposit over a path length that exceeds 1000 m. The distribution of banded quartz and gold at Golden Cross are consistent with such a boiling model. However, the elevation of first boiling must have fluctuated over 500 m to account for the coincidence of lattice quartz (pseudomorphs of platy calcite) and adularia, crustiform-colloform silica and gold over distances of a few centimeters in veins. We deduce that a downward propagating boiling front and expansion of two-phase flashing in a flowing water column occurred during episodes of high vertical permeability and fluid flux in the Empire vein structure.

Jan 1, 2000

By Fred P. Giese

Southeastern reserves of titanium ores are large, widespread, and ample for anticipated demand. The leading titanium industries are mining and beneficiating sand deposits, principally in Florida, and manufacturing titanium pigments. Most of the mineral output is consumed by the producers themselves. In 1962, 20 percent of the national pigment capacity was in the Southeast.

Jan 1, 1964

Same-batch and non-blind as well as blind pulp duplicates are often submitted as quality assurance/quality control (QA/QC) control samples to a routine laboratory along with routine assays (and other control samples such as reference material samples). The current ways of interpreting the results of duplicate assays to derive QA/QC conclusions and decisions, however, has not yet been formalised in a scientific manner. The current, prevailing approach and its limitations are reviewed and a new method is proposed as a substitute tool. This new tool should allow for operational error detection on a batch per batch basis (ie batch rejection) as well as laboratory performance assessment with time on reproducibility.

Jan 1, 2008

By Jennifer Pell

Dunsmuir Ventures? Nanuq diamond project is located approximately 250 km northeast of Baker Lake and 170 km north of Chesterfield Inlet. It occurs at the intersection of the Wager Bay shear zone with the Keewatin Arch, a major long-lived crustal uplift. The newly discovered diamondiferous kimberlites at Rankin Inlet, Repulse Bay and on Melville Peninsula also occur along this arch. Kimberlite indicator mineral (KIM) sampling has outlined a distinct KIM train more than 35 km long and 6 km wide. Geomorphological studies, boulder displacements and dispersion of magnetite in tills suggest that glacial transport distances were on the order of 4 to 6 kms only. The presence of multiple sources within the main Nanuq indicator train would account for its length and breadth. A second train has been located on the west central part of the property and anomalous concentrations of KIM occur elsewhere. Pyrope garnets (G9?s and G10?s), diamond inclusion field (DI) eclogitic garnets and DI chromites were confirmed by microprobe analyses. Clinopyroxene thermobarometry indicates a cool geotherm, approximately 35 mW/m2, and that mantle within the diamond stability field was tapped. An aeromagnetic survey has identified a number of anomalies. Those with down ice KIM support will have ground geophysical follow-up and will be tested in a spring 2004 drill program. Dunsmuir is optimistic that this will lead to the discovery of a new kimberlite cluster on the Nanuq property.

May 1, 2004

By B. S. Terry, C. L. Harris

Reduction kinetics from slags containing CuO(0.5), ZnO, PbO, NiO and SnO into a Cu-based metal phase were subjected to computer simulation using a previously developed model for the kinetics of metal-slag-gas reactions that assumes mass-transfer control in all phases. The effects were examined of changing bulk Fe oxide activity, gas reducing potential, temperature, Fe content of the Cu phase and metal/slag ratio. The results permit practical conclusions to be drawn about industrial slag-cleaning practice, but the model is still limited in terms of thermodynamic inputs and the idealisation of reaction conditions

Aug 1, 1995

By C. Roos, K. Jetmore

Developing a strategic underground mine plan is challenging and investigating multiple scenarios may take weeks. This process can be sped up using the Theory of Constraints to isolate the bottleneck mining activity and simplify the mine schedule process. This paper presents a technique to apply the Theory of Constraints to test multiple cutoff grade scenarios in Mineable Shape Optimiser and quickly produce many high-level production-based schedules that can be easily interpreted using stope-by-stope graphs, the Hill of Value, and through incremental return analysis.

Mar 2, 2022

By Roy F. Abernethy

All samples tested showed some loss of heating value for the 5-month period under all 4 storage conditions. The losses increased as the time of storage increased, with the pan-storage samples showing somewhat greater losses than those in cans. The individual daily analyses for the first 2 weeks and the analyses every other day for the third and fourth weeks of storage vary within the approximate tolerance of the test for heating value. During the first 2 months of storage the changes in heating values were not Significant for the samples from Pennsylvania, Indiana, and Colorado. The Ohio coal indicated some loss by the end of I month, which increased to a value measurable with certainty by the end of 2 months. These data show that (1) small changes may occur even to samples in closed cans and (2) the laboratory sample should be handled as expeditiously as is practical until the analysis is completed. The statement by the ASTM that "If the B.t.u. determination is an important consideration in the sale of coal, the time elapsed between sampling and analysis shall not exceed 30 days,"3/ is quite adequate for 3 of the 4 coals tested. The change in the Ohio coal stored for 30 days is merely indicated and could not be determined with certainty by the techniques normally employed. The data on free-swelling indexes determined on can samples, after 30° C. air drying, show that only the Indiana coal lost more than one unit in free-swelling index number in 120 days. No significant changes were observed with the samples from Pennsylvania, Ohio, and Colorado in the 5-month period.

Jan 1, 1958

By J. P. Cooney

Placer Dome is learning from experience in Latin America, Asia and Africa, as well as in North America, that contributing effectively to sustainable human progress in the areas of its operations presents unending challenges to think creatively, communicate effectively and remain culturally sensitive. People must be better off in terms of their economic circumstances, their social conditions and the quality of their natural environment not only during the life of the mines, but after mines close. Stakeholders, all those who are directly or indirectly affected by a mining project, should be able to participate in decisions which affect them. The development of sustainability strategies, the monitoring of sustainability performance and the implementation of sustainability programs are best done in partnerships with governments, communities, nongovernmental organizations and multilateral development institutions. Ultimately, the success, if not the survival of mining, will depend on our ability to get the sustainability equation correct.

Jan 1, 2000